I (25m) have lost a friend because she (27f) got back with her ex, whom she knows is not right for her.

I made a thread not too long ago about how my friend was recently dumped and how sad and depressed she was and I was trying my best to be there for her. Well this past week she decided to wait for him in hopes of coming back. For the week she told me a little more about this guy that I had previously not known, he has two failed marriages, 2 children and his second wife still lives with him (plans on moving out in July apparently though), among other things that would raise a ton of red flags.

She kept coming to me for advice on the matter and every time I would voice my opinions and concerns (when she asked) she would always brush my feelings aside. Now this initially didnt bother me much, I shouldn't be the one making her decisions, however she told me Wednesday night that the main reason she is waiting is because she doesn't want to be lonely. When she told me this I explained to her that wanting to be with someone simply because you're afraid of loneliness is a horrible reason. She got quiet upset by this and basically told me that if I were really her friend I'd support her no questions asked. The thing is, I had been supporting her emotionally for the past two weeks or so, I constantly had to hear about how sad she was and stuff. Her other friends basically told her to grow up and move on, and she thought I'd be more understanding. I was quiet hurt by this and left her apartment without saying much. The next day she tells me that her and her ex are meeting up Friday night to talk things over. I didn't respond because I was still upset about what she said. Later that night she tells me that I'm clearly not the friend she thought I was since I'm just ignoring her. I didn't want to start a fight or anything, so I told her that I want to be there and be supportive as a friend but I can't sit by and watch as she potentially sets herself up for heartache with a man who will likely never be fully committed to her. I told her she was like a sister to me and that I'd always love her and care for her, but that I can't be her constant crutch emotionally because it was draining me emotionally.

Last night, after two days of not speaking she informs me she got back together with this guy. When I read the text I literally shook my head and felt a wave of disappointment go through me. I asked her why, after everything she told me about this guy, after all the heartache she went through, why get back together? She told me that I truly didnt understand her, that a true friend would be happy for her and that I'd understand her decision without having to ask. When she said this I realized that I can't sit by and watch someone I care about put themselves in a situation that will likely end with her getting hurt again. I listed all the reasons she gave me for why she felt he may not all that great for her (she gave me these reasons days after he dumped her), I reminded her how much it hurt when he dumped her.

She basically told me to fuck off and that she can make her own decisions and doesn't deserve criticism from someone like me.

Also before anyone says, I am not in love with her, but yes, I do love her. I have been seeing a wonderful lady for the past 2 weeks as well.

TL;DR: Friend gets dumped, comes to me for support, give her my full support, starts to get mad when I disagree with her decision to wait for her ex, breaks off friendship with me after getting back with her ex and me disapproving of it. I feel lost and hurt.